Will a Solid Flat tappet cam make more power or be the same as a roller??
Here's my thoughts on it, and I'll explain why I feel this way afterwords.
I don't feel solid rollers are enough of a benefit to justify the cost over a solid flat tappet cam unless; A: your motor is spinning 8000+ rpm, or B: already making in excess of 750 hp.
Here's why I think this. A few years back I was running a solid roller in my racecar. It was running consistantly low 6.40's in the heat of the summer shifting at 7500 rpm (so consistantly in fact, I showed up at the track 3 weeks in a row with the same dial-in on the window; 6.43.) Well, my first time run of this particular weekend the motor sheared the cam pin (something solid roller cammed Ford's are notorious for doing.) Well, I didn't have another roller cam AND lifters (my lifters were all damaged when the cam stopped, the crank didn't, and the pistons met the valves at a high rate of speed.) But, I did have a solid flat tappet that was very similar to the roller. My roller was 264/272 @ .050, .650/.650 lift, 108 lsa. The solid cam was 266/277 @ 050, .625/.623 lift 107 lsa.
Since I was second in points, we didn't have time to get the lifters rebuilt, and I couldn't afford to buy new ones and replace all the bent valves. So instead, I opted to buy new springs and drop the solid cam in. Well, the first pass with it, the car ran the same 60' time it had been, same half track time, SAME ET and mph as it did with the roller. It ran a 6.43 first pass and everyone thought I had put the roller back in. And to top it off, the car ran the quickest 1/4 mile to date with that cam, 9.97.
Oh yeah, this was all in an 11-1 compression iron headed 357 inch cleveland.